A lot has changed. In RiF, they have dex bonus in non-wing form, in wing form they have regen buffed. They can have very good int and con, so it's really easy. Proccer. The only downside is you need a buffbot for the second proc, because they cannot take UH and sadly not even runecaster. That's probably why you don't see them very often.

For actual scouting, you'd be best off with a bow for the GM weapon powers. But dex on a neph is a problem, even with the human-form dex buff. You could build it to use dex and bow, but it will be pretty inferior to any other scout. I could see doing this out of necessity for a chaos lore guild.

Proccing with throwing daggers is probably the most viable way to build it. Stay in neph form and use the health regen.

You could also build it to use a pair of swords. It would do decent damage, but it would have problems against def builds because it has no def cut. And you have to run up to people to pop them from stealth because you can't just shoot them at range.

Finally, you could be wacky. Take Proficient with Axes at creation. Raise dagger high enough to unlock Throwing. Use throwing axes for decent damage and some form of range.

I would recommend hone/proc bots for any of these builds as a crutch to make them more likely to work.

Master spies and infiltrators, the Nephilim have spread throughout Aerynth in secret, and perhaps only the Dark Lords know precisely how many there are.